Oscillators are electronic circuits that output oscillating currents or voltages (e.g., sine waves) by converting a direct current (DC) signal into an alternating current (AC) signal. Oscillator circuits have practical applications in devices that use frequency tuners, filters, modulators, etc. One of these applications includes using an oscillator circuit as part of a start-up circuit for a hard disk drive (HDD) or other storage device in a processing device (e.g., a personal computer). One type of oscillator useful for the startup circuit is a crystal oscillator comprised of a piezoelectric crystal, for example, quartz. In operation, the piezoelectric crystal's frequency of vibration determines the oscillation frequency of the output signal of the oscillator circuit while the amplitude of a DC input signal determines the amplitude of the output signal.
A desirable trait in many modern computers or processing devices is the ability to quickly switch from a reduced power mode (e.g., a sleep mode) to a normal mode. One of the factors that affects this ability to switch between modes is the speed at which the aforementioned startup circuit can “wake up” the storage device from such a reduced power mode.